Topic 4 - Natural selection and Genetic Modification

Question 1

Darwin discovered

Answer 1

The theory of evolution by natural selection. He found on a voyage that there was variation in members of the same species due to the environment.

Question 2

Wallace discovered

Answer 2

The same theory of evolution but with different discoveries, such as warning colours on some species to deter predators

Question 3

How do Darwins and Wallaces discoveries affect modern biology

Answer 3

Classification by relation
Antibiotic resistance
Conservation to protect diversity

Question 4

What is natural selection

Answer 4

Survival of the fittest. The individuals with characteristics that are better adapted to surroundings survive. Those that dont more likely to die. The survived reproduce and pass on the charcteristic.

Question 5

How do bacteria provide evidence for evolution

Answer 5

Mutations lead to new alleles and characteristics. This can lead to antibiotic resistance. The ones with this survive and reproduce and become mroe common.

Question 6

How do fossils provide evidence for evolution

Answer 6

By arranging fossils in chronological order, changes in organisms can be observed.

Question 7

Fossils suggest what about human ancestors

Answer 7

That humans and chimpanzees evolved from a common ancestor. Fossils of many hominid(humans and ancestors) species have been found that show similarities

Question 8

The three hominid fossils we need to know about are

Answer 8

Ardi - 4.4 million yrs old
Lucy - 3.2 million yrs old
Leakeys fossils - 1.6 million yrs old

Question 9

Ardi features

Answer 9

Tree climbing feet
Long arms and short legs
Chimpanzee size brain
Legs that walked upright without hands

Question 10

Lucy features

Answer 10

Arched feet
Arm and leg length between apes and humans
Slightly bigger than chimp brain
Walked upright quite efficiently

Question 11

Leakey features

Answer 11

More human like than lucy
Short arms long legs
Almost human brain size
Efficient upright walking feet

Question 12

Homo habilis(2.5 - 1.5m years ago) stone tools

Answer 12

Simple tools made by hitting small rocks together to create sharp ends.
Used to scrape meat from bones or crack bones open

Question 13

Homo erectus(2-0.3m yrs ago) stone tools

Answer 13

Sculpted rocks into complex tools like simple hand axes. Hunting , digging, chopping.

Question 14

Homo neanderthalensis(300,000-25,000 yrs ago) stone tools

Answer 14

Complex tools. Evidence fo flint tools, pointed tools and wooden spears

Question 15

Homo sapiens(200,000 yrs ago - present) stone tools

Answer 15

Flint tools. Pointed tools including arrowheads. Fish hooks and needles

Question 16

Methods of dating stone tools

Answer 16

Looking at the structural features.
Statigraphy - Study of rock layers. Deeper=older.
Carbon-14 dating: stone tools often have carbon.

Question 17

What is a pentadactyl limb

Answer 17

A limb with five digits

Question 18

Pentadactyl limbs in different species shows

Answer 18

That the species evolved from a common ancestor

Question 19

The five kingdom calssification includes

Answer 19

Animals
Plants
Fungi
Prokaryotes - Single-celled organisms without a nucleus
Protists - Single-celled organisms with nucleus

Question 20

After being categorised into the 5 kingdoms, they can be subdivided further into

Answer 20

Phylum, class, order, family, genus, species

Question 21

The new and improved classification system includes

Answer 21

Archaea - Look similar to bacteria but are much different in their DNA and RNA sequences
Bacteria - True bacteria like E.coli
Eukarya - A broad range of organisms - Fungi, plants, animals, protists

Question 22

The reason for the change in organism classification is

Answer 22

Genetic analysis

Question 23

Selective breeding is where

Answer 23

Organisms that have desirable features are bred more.

Question 24

Process of selective breeding

Answer 24

Pick desirbale ones form existing stock
Breed with eacother
Select the best of the offspring and breed them
Continue this over many generations to maximize the characteristic

Question 25

Selective breeding 2 advanatges

Answer 25

Better yield and betetr revenue Medical studies

Question 26

Selective breeding 3 disadvantages

Answer 26

Reduces the gene pool leads to inbreeding Leads to health problems as there is more chance of getting genetic defects If a new disease appears it could kill off the whole population

Question 27

Tissue culture is

Answer 27

Growing cells on an artificial grwoth medium using other organisms tissue

Question 28

Plant tissue culture process

Answer 28

Choose plant to be cloned Remove several pieces of tissue, preferrably from fast-grwoing root or shoot tips Grow tissue in growth medium with nutrients and growth hormone In aseptic conditions to prevdnt microbe growth Allow tissue to grow then transfer to potting compost

Question 29

Plant tissue culture advantages

Answer 29

Easy to do Quick to grow plants Very little space Grown all year Genetically identical to get desirable chracteristic

Question 30

Animal tissue culture process

Answer 30

A sample of tissue is extracted Cells are seperated with enzymes Placed in culture vessel and bathed in growth medium with nutrients They grwo and multiply This is repeated once multiplied and allowed to grow more Then its stored for future use

Question 31

Animal tissue culture advantages

Answer 31

Investigates effects pf a particluar substance pm the cells of a single tissue, rather than risking it on a whoel organism.

Question 32

Genetic engineering is

Answer 32

Modifying an organisms genome to introduce desirable charcteristics.

Question 33

Restricition enzymes role

Answer 33

Recognise specific sequences of DNA and cut the DNA at these points. leaves dna with sticky ends that match the desired base.

Question 34

Ligase enzymes role

Answer 34

Used to jon two pieces of DNA together at the sticky ends

Question 35

Recombinant DNA is

Answer 35

Two different bits of DNA stuck together

Question 36

A vector is

Answer 36

Something used to transfer DNA into a cell

Question 37

2 types of vectors

Answer 37

Plasmids and viruses

Question 38

Plasmids are

Answer 38

Small circular molecules of DNA that can be transferred between bacteria

Question 39

Viruses are

Answer 39

Things that insert DNA into the infected organism

Question 40

Genetic engineering process

Answer 40

1. DNA to be inserted is cut out with a restriciton enzyme with sticky ends 2. vector DNA also cut open with restriciton enzyme 3. The vectro DNA and DNA insterted have their sticky ends joind by a ligase enzyme to make a recombinant DNA 4. The recombinant DNA is inserted into another cell(often fast multiplying liek bacteria) 5. This multiplies and gives the product or charcteristici wanted

Question 41

Crops can be GM to be

Answer 41

Resistant to insects

Question 42

insect resistant crop GM process

Answer 42

Bt(Bacillus thuringiensis) inserted into DNA whioch produces a toxin that kills insects. It is harmless to humans and animals.

Question 43

What is inserted into crops to make them insect resistant

Answer 43

Bt(Bacillus thuringiensis)

Question 44

Advantages of GM crops for food security

Answer 44

Increase food production Pest resistance Cope with harsh conditions Combat deficiency diseases

Question 45

disadvantages of GM crops for food security

Answer 45

Poverty may be the real issue not food production Countries may become reliant on GM foods Poor soil is often the main reason for lack of crop

Question 45

Benefits of GM in agriculture and medicine

Answer 45

Increased crop yield Production of human proteins Help produce preventions to disease

Question 46

Risks of GM in agriculture and medicine

Answer 46

Death of animals Health problems for animals GM crops could get into weeds and create superweeds

Question 47

Other methods of increasing food production other than GM

Answer 47

Fertilisers that provide nutrients. Can lead to eutrophication. Bioligical control - Using other organisms to reduce pest numbers